:root {
  --scroll: 0px;
  --visible: 170;
  --accent: #59363c;
  --background: #f4efe9;

  font-family: "Times New Roman", serif;
  word-spacing: 0.3em;
  letter-spacing: -0.09em;
  text-underline-offset: 3px;
  color: var(--accent);
  scroll-behavior: smooth;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  background: var(--background);
}

/* tall scroll track; the scene itself stays pinned */
body {
  height: 18000px;
}

h1,
h2,
nav,
#link,
.hint {
  font-family: "Helvetica", Arial, sans-serif;
}

h1 {
  margin: 0;
  font-weight: 400;
  text-transform: uppercase;
  font-size: clamp(2.2rem, 9vw, 4rem);
  text-align: center;
  width: 100%;
  line-height: 1em;
  padding: 0 1rem;
  letter-spacing: -0.04em;
}

h2 {
  margin: 0;
  font-size: 1.125rem;
  text-transform: uppercase;
  letter-spacing: -0.05em;
  font-weight: 600;
  width: 100%;
  text-align: center;
}

nav {
  display: flex;
  flex-direction: row;
  gap: 1rem;
  justify-content: center;
}

nav a {
  color: var(--accent);
  text-transform: uppercase;
}

.hint {
  text-align: center;
  text-transform: uppercase;
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  opacity: 0.7;
  animation: bob 2.2s ease-in-out infinite;
}

@keyframes bob {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(6px); }
}

header,
footer {
  display: flex;
  flex-direction: column;
  text-align: center;
  gap: 1rem;
}

header {
  z-index: 100;
  position: relative;
  top: calc(100dvh - 12rem);
  padding: 0 1rem;
}

/* ---- panels / frames ---- */
article {
  border: 3px solid var(--accent);
  border-bottom: none;
}

p,
pre {
  margin: 0;
}

pre {
  font-family: monospace;
  letter-spacing: normal;
  word-spacing: normal;
}

.title,
.author {
  position: absolute;
  padding: 1rem;
  font-size: clamp(1.7rem, 5vw, 2.5rem);
}

.title {
  width: calc(100% - 4rem);
  z-index: 1;
  left: 0;
  top: 0;
}

#link,
.title {
  color: var(--accent);
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
  text-decoration: underline;
  text-decoration-style: dotted;
}

#link:hover,
.title:hover {
  text-decoration-style: solid;
}

.author {
  right: 0;
  bottom: 100%;
  text-align: right;
  display: flex;
  align-items: flex-end;
  justify-content: right;
  transform: rotate(90deg) translate(100%, 4rem);
  width: max-content;
  height: min-content;
  transform-origin: bottom right;
}

.description {
  padding: 0 0.5rem;
  bottom: 0;
  width: 100%;
  position: absolute;
  font-size: clamp(1.4rem, 4.5vw, 2rem);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  align-items: center;
  text-align: justify;
}

.description,
.description a {
  color: inherit;
  text-decoration: none;
}

.description a {
  display: block;
}

.description p {
  background: var(--background);
  line-height: 110%;
  max-width: 40rem;
  padding-top: 14rem;
}

.ascii .description pre {
  font-size: clamp(0.7rem, 2.4vw, 1.2rem);
}

/* extended side slabs to make the corridor read as continuous walls.
   Kept modest (150vw) so the GPU backing store stays small on high-DPR
   phones; the body background (same colour) covers anything beyond. */
article:after {
  left: 100vw;
  margin-left: -6px;
  border-left: 3px solid var(--accent);
}

article:before {
  left: -150vw;
  margin-left: -2px;
  border-right: 3px solid var(--accent);
}

article:after,
article:before {
  content: "";
  position: absolute;
  width: 150vw;
  border-bottom: 3px solid var(--accent);
  bottom: 0;
  height: 100%;
  background: var(--background);
}

/* ---- floating "enter" doorway ---- */
#link {
  position: fixed;
  font-size: 1.125rem;
  padding: 1.1rem 1.25rem;
  background: yellow;
  border: 1px solid;
  transform: translate(-50%, -50%);
  top: calc(100dvh - 4.5rem);
  left: 50%;
  text-align: center;
  letter-spacing: -0.03em;
  word-spacing: 0.2em;
  width: max-content;
  max-width: 90%;
  display: none;
  z-index: 200;
}

footer {
  position: fixed;
  width: 100%;
  left: 50%;
  bottom: 3rem;
  transform: translateX(-50%);
  opacity: calc(31 + -1 * var(--visible));
  z-index: 100;
}

/* ============================================================
   THE 3D TUNNEL  (applied on every screen size)
   Each panel sits 1000px deeper than the last; --scroll pulls
   the whole stack toward the camera as you scroll.
   ============================================================ */
main {
  perspective: 600px;
  height: 100dvh;
  width: 100vw;
  position: fixed;
  top: 0;
  overflow: hidden;
}

article {
  position: absolute;
  width: 100vw;
  margin: 0;
  height: calc(100dvh - 6rem);
  /* Only the 12 panels are GPU-composited (they carry a 3D transform);
     opacity + display are driven from JS so far/passed panels are culled
     and never allocate a backing store on memory-constrained phones. */
  backface-visibility: hidden;
  opacity: 0;
}

article:nth-child(1)  { transform: translateZ(calc(var(--scroll) - 2500px));  z-index: 20; }
article:nth-child(2)  { transform: translateZ(calc(var(--scroll) - 3500px));  z-index: 19; }
article:nth-child(3)  { transform: translateZ(calc(var(--scroll) - 4500px));  z-index: 18; }
article:nth-child(4)  { transform: translateZ(calc(var(--scroll) - 5500px));  z-index: 17; }
article:nth-child(5)  { transform: translateZ(calc(var(--scroll) - 6500px));  z-index: 16; }
article:nth-child(6)  { transform: translateZ(calc(var(--scroll) - 7500px));  z-index: 15; }
article:nth-child(7)  { transform: translateZ(calc(var(--scroll) - 8500px));  z-index: 14; }
article:nth-child(8)  { transform: translateZ(calc(var(--scroll) - 9500px));  z-index: 13; }
article:nth-child(9)  { transform: translateZ(calc(var(--scroll) - 10500px)); z-index: 12; }
article:nth-child(10) { transform: translateZ(calc(var(--scroll) - 11500px)); z-index: 11; }
article:nth-child(11) { transform: translateZ(calc(var(--scroll) - 12500px)); z-index: 10; }
article:nth-child(12) { transform: translateZ(calc(var(--scroll) - 13500px)); z-index: 9;  }

/* slightly gentler depth + bigger type on small screens */
@media screen and (max-width: 800px) {
  main { perspective: 520px; }
  .description p { padding-top: 9rem; }
}

/* ---- calm fallback: no flight, just a vertical list ---- */
@media (prefers-reduced-motion: reduce) {
  :root { scroll-behavior: auto; }
  body { height: auto; }
  main {
    position: relative;
    perspective: none;
    height: auto;
    overflow: visible;
  }
  header { top: 0; padding: 6rem 1rem 3rem; }
  article {
    position: relative;
    transform: none !important;
    opacity: 1 !important;
    width: 84vw;
    height: 70vh;
    margin: 6rem 8vw;
  }
  article:after { left: 84vw; width: 8vw; }
  .description p { padding-top: 0; -webkit-mask-image: none; mask-image: none; }
  footer { position: relative; opacity: 1; margin-top: 6rem; bottom: 0; padding-bottom: 6rem; }
  #link { display: none !important; }
}